Woody IPv6 problem finally, really, solved

[Jan Willem Stumpel <jstumpel@planet.nl>]

Searching the archives of this list for "IPv6" I found I was not 
the only one with problems like "local domains always resolved 
through dialup interface", "unable to disable IPv6 for some 
reason", "DNS madness on Woody", and other problems with "local 
address lookup".

With the help of the IPv6 developer list I finally found the real 
solution: Woody versions of some Debian packages, like telnet, 
and, it seems, exim, *require* IPv6 addresses for your local 
machines (including localhost!) in /etc/hosts, or they will call 
your ISP to ask for them. And of course your ISP's nameservers 
don't have them either. Specifying local lookup ("files") in 
/etc/nsswitch.conf does not help.

So if your /etc/hosts is, for instance:

127.0.0.1       localhost
192.168.1.1     mars.my.home  	 mars
192.168.1.2     jupiter.my.home  jupiter
192.168.1.3     venus.my.home    venus

Then at the end of the file you have to add

::FFFF:127.0.0.1       localhost
::FFFF:192.168.1.1     mars.my.home  	mars
::FFFF:192.168.1.2     jupiter.my.home  jupiter
::FFFF:192.168.1.3     venus.my.home    venus

The stuff already added to /etc/hosts by the Woody upgrade 
process, like

::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet

etc., should remain where it is.

I have no idea why this new behaviour of the packages should be a 
Good Thing (a ploy to harass ISP's, to force them to support IPv6, 
perhaps?), but at least I have now restored some sanity to my 
system.

Regards, Jan